1. Field
The present invention relates to a reflective bank structure for light emitting devices. More particularly, embodiments of the present invention relate to a reflective bank structure for light emitting diode devices.
2. Background Information
Light emitting diode (LED) devices may include a p-type semiconductor layer, an n-type semiconductor layer, and one or more quantum well layers between the p-type semiconductor layer and the n-type semiconductor layer. The light emitting efficiency of a LED device system depends upon the internal quantum efficiency of the quantum well layer(s) and the light extraction efficiency from the system.
One implementation for increasing light extraction efficiency has been to include a reflective layer in the electrode layer opposite the light emission direction. For example, for a top emission structure, the bottom electrode may include a reflective layer, and vice versa. Light emitting from the lateral surfaces of a LED device may decrease light extraction efficiency.
One implementation for increasing light extraction efficiency from a horizontal LED chip is described in U.S. Pat. No. 7,482,696 in which a horizontal LED chip is placed within a cavity of an insulating submount with a pair of conductive-reflective films on sidewalls of the cavity. An n-side electrode on a bottom side surface of the horizontal LED chip is flip chip bonded to a pad on one of the conductive-reflective films, and a p-side electrode on the bottom side surface of the horizontal LED chip is flip chip bonded to a pad on the other conductive-reflective film. In this manner, the horizontal LED chip is packaged within the submount, and lateral emission through the side surfaces of the horizontal LED chip is reflected to increase light extraction efficiency of the package.
One implementation for increasing light extraction efficiency from a vertical LED device system is described in U.S. Pat. No. 7,884,543 in which a light emitting surface of the vertical LED device is mounted on a narrow wiring in a transparent substrate. A transparent resin is formed over and around the vertical LED device, and a reflective film is deposited over the transparent resin and the vertical LED device to direct light toward the light emitting surface.